MANURING OF SWEDES. 2103 

Plots 8, 10, 11 and 12 show the average results obtained 
by the use of artificials alone. Compared with the unma- 
nured plot (Plot 1) the use of superphosphate increased the - 
yield; the addition of sulphate of ammonia was also accom- 
panied by an increase ; but the application of sulphate of 
potash together with superphosphate and sulphate of am- 
monia had a greater influence than either of the other 
dressings, though, owing to the smallness of the crop and the 
comparatively high cost of the sulphate of potash, the 
increased yield was not profitable last year. As in the case 
of the dunged plots, in this series alsoa plot (Plot 12) was 
tried with a double dressing of superphosphate, but here 
again the additional application of 4 cwts., of superphos- 
phate was ineffective, as will be seen on comparing the 
yields obtained on Plots 11 and 12. 
The effects of the use of dung are brought out by compar- 
ing the results obtained on the dunged and undunged plots 
as follows :— 

Increase Increase 
| Yield per per Acre Yield per per Acre 
Plots. Manures per Acre. Acre zwzth over ten Acre with- over un- 
Dung. tons Dung | out Dung. manured 
alone. Plot. 


Tons cwts. | Tons cwts. | Tons cwts.| Tons cwts. 
3and8. | 4 cwt. Super. . - - - | 10 15 I 9 8 3 fo) 17 
sand ro. | 4 cwt. Super. - - a 
r cwt. Sulph. of Amm. ie *3 eS 7 8 sll z EY 
6and rz, | 4 cwt. Super. - - 
1 cwt. Sulph. of Amm. 
2 cwt. Sulph. of Potash 



=——_—_—"—_ — = 


This comparison, Professor Campbell remarks, brings out 
what appears to be a fundamental principle which should 
govern the manuring of roots, viz., that where dung is 
applied, the application of nitrogen and potash in the form 
of artificials is unnecessary, but where farmyard manure is 
not applied, not only the nitrogen, but also the potash, must 
be included in the mixture. 

EXPERIMENTS IN MANURING POTATOES. 
Experiments on the growth of different varieties of potatoes 
under various systems of manuring have been carried out 
